Intelligent Computational Paradigms in Earthquake Engineering. Sailing the Gulf of 3D Digital Content Creation. Meeting National Needs Through Enhanced. Reliable analysis of low-energy earthquakes (microseismic) depends on how accurately one can detect and pick the arrival times, which are strongly influenced by the noise content. The study of.

The 2011 Tohoku earthquake (M w = 9.1) highlighted previously unobserved features for megathrust events, such as the large slip in a relatively limited area and the shallow rupture propagation. We use a Finite Element Model (FEM), taking into account the 3D geometrical and structural complexities up to the trench zone, and perform a joint inversion of tsunami and geodetic data to retrieve the earthquake slip distribution. We obtain a close spatial correlation between the main deep slip patch and the local seismic velocity anomalies, and large shallow slip extending also to the North coherently with a seismically observed low-frequency radiation. These observations suggest that the friction controlled the rupture, initially confining the deeper rupture and then driving its propagation up to the trench, where it spreads laterally.

These findings are relevant to earthquake and tsunami hazard assessment because they may help to detect regions likely prone to rupture along the megathrust, and to constrain the probability of high slip near the trench. Our estimate of ~40 m slip value around the JFAST (Japan Trench Fast Drilling Project) drilling zone contributes to constrain the dynamic shear stress and friction coefficient of the fault obtained by temperature measurements to ~0.68 MPa and ~0.10, respectively. On March 11 th 2011 one of the largest earthquakes ever recorded occurred at the subduction interface between the Pacific and the Okhotsk plates and struck the Tohoku region in Japan (). This M w9.1 earthquake, located at 142.68°E 38.19°N, generated a tsunami that devastated the Japanese coasts, including towns and important infrastructures such as the Sendai airport and the Fukushima nuclear power plant causing more than 16,000 fatalities. The Tohoku earthquake is also the best observed ever megathrust event and consequently it has been investigated by modelling the unprecedented high-quality data set recorded by the Japanese dense seismological, geodetic and marine observational networks. The numerous studies published in recent literature are based on different kind of data and methodologies, including teleseismic, strong motion, geodetic,,, tsunami waveforms,, and joint inversions,, which were performed to investigate the earthquake rupture process. (a) Red star indicates the epicentre position.

Red and white “beach ball” represents the focal mechanism of 2011 Tohoku earthquake. Yellow triangles indicate the DART stations used in the inversion; (b) Cyan circles indicate GPS stations onshore, magenta circles indicate the geodetic seafloor observation sites, yellow triangles indicate the bottom pressure sensors and GPS-buoys (). White arrow indicates the approximate convergence direction of the Pacific plate (estimated velocity of 9.2 cm/yr). Maps are created using GMT (Generic Mapping Tools, ) software. The resulting source models share two common features of the coseismic rupture, stimulating further investigations to explore the physical processes controlling the genesis and the impact of megathrust events.